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Selenium disulfide, also known as selenium sulfide, is a chemical compound and medication used to treat seborrheic dermatitis, dandruff, and pityriasis versicolor. Use is not recommended in children less than 2–5 years old. It consists of a mixture of inorganic covalent compounds having an approximate empirical formulas of SeS<sub>2</sub>. Selenium disulfide acts as a keratolytic and antifungal agent.

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Selenium disulfide was approved for medical use in the United States at least as early as 1951. It is on the World Health Organization's List of Essential Medicines. Selenium disulfide is available as a generic medication and over the counter.

Medical uses

Selenium disulfide is sold as an antifungal agent in shampoos (such as Selsun Blue) for the treatment of dandruff and seborrheic dermatitis associated in the scalp with fungi of genus Malassezia. It is also used on the body to treat tinea versicolor (pityriasis versicolor), a type of fungal skin infection caused by a different species of Malassezia.

A 2015 systematic review of topical treatments for seborrheic dermatitis of the scalp identified only a single randomized controlled trial evaluating selenium disulfide for the condition. It was a three-arm trial of 246 people with moderate to severe dandruff and compared treatment with 2% ketoconazole shampoo (n=97), 2.5% selenium disulfide shampoo (n=100), and placebo (shampoo base with no antiseborrheic agent) (n=49) for 29days. The study found a 73% reduction in dandruff score with ketoconazole, a 67% reduction with selenium disulfide, and a 45% reduction with placebo. However, the review did suggest use of over-the-counter selenium disulfide shampoos as an inexpensive option for managing mild symptoms of seborrheic dermatitis. In Canada, the 2.5% strength is available over-the-counter. The discoloration resolved shortly following discontinuation of selenium disulfide shampoo and its removal could be facilitated by lightly swabbing with isopropyl alcohol. Excessive environmental or occupational exposure to selenium has also been associated with hair loss and other adverse effects. However, application of selenium disulfide to damaged skin can result in systemic absorption and has been associated with cases of toxicity.

Many selenium sulfides are known, as indicated by <sup>77</sup>Se-NMR spectroscopy.

History

Selenium sulfide was introduced for medical use in the United States in 1951. causing confusion and contradiction as to exactly what form selenium is in any given topical preparation.

Society and culture

In the 2001 comedy film Evolution selenium was mentioned as an active ingredient of the anti-dandruff shampoo Head & Shoulders. A group of academics, therefore, tried to use this brand of shampoo to stop an alien invasion after discovering that the alien life form was sensitive to selenium.

Research

Selenium disulfide has been suggested to be effective as a treatment for hyperkeratosis based on a small case series of three treated patients. It has also been reported to be effective in the treatment of scalp psoriasis based on clinical observation of over 100treated patients and two case reports of dramatic response.

Selenium sulfide is under development for the treatment of meibomianitis (meibomian gland dysfunction) and dry eyes in topical and ophthalmic formulations.